This invention relates to rotary piston and cylinder devices which may be, for example, in the form of an internal combustion engine, or a pump such as a supercharger or fluid pump, or as an expander such as a steam engine or turbine replacement.
The term ‘piston’ is used herein in its widest sense to include, where the context admits, a partition capable of moving relative to a cylinder wall, and such partition need not generally be of substantial thickness in the direction of relative movement but can often be in the form of a blade. The partition may be of substantial thickness or may be hollow.
The invention relates in particular to a rotary piston and cylinder devices of the type comprising a rotor and a stator, the stator at least partially defining an annular cylinder space, the rotor is in the form of a ring, and the rotor comprising at least one piston which extends from the rotor ring into the annular cylinder space, in use the at least one piston is moved circumferentially through the annular cylinder space on rotation of the rotor relative to the stator, the rotor body being sealed relative to the stator, and the device further comprising cylinder space shutter means which is capable of being moved relative to the stator to a closed position in which the shutter means partitions the annular cylinder space, and to an open position in which the shutter means permits passage of the at least one piston, the cylinder space shutter means comprising a shutter disc.
In a highly preferred embodiment the at least one piston extends generally inwardly from the rotor ring and the stator is positioned generally internally of the ring.
The stator may have portions which extend generally radially outwardly beyond the ring if desired.
Preferably the shutter disc presents a partition which extends substantially radially of the annular cylinder space.
Although in theory the shutter means could be reciprocable, it is much preferred to avoid the use of reciprocating components, particularly when high speeds are required, and the shutter means is preferably at least one rotary shutter disc provided with at least one aperture which in the open condition of the shutter means is arranged to be positioned substantially in register with the circumferentially-extending bore of the annular cylinder space to permit passage of the at least one piston through the shutter disc.
Preferably the at least one aperture is provided radially in the shutter disc.
Preferably the rotor is adapted to receive the shutter disc.
The shutter disc is preferably driven from the rotor through a suitable transmission means.
Preferably the axis of rotation of the rotor is not parallel to the axis of rotation of the shutter disc. Most preferably the axis of rotation of the rotor is substantially orthogonal to the axis of rotation of the shutter disc.
Preferably the piston is so shaped that it will pass through an aperture in the moving shutter means, without balking, as the aperture passes through the annular cylinder space. The piston is preferably shaped so that there is minimal clearance between the piston and the aperture in the shutter means, such that a seal is formed as the piston passes through the aperture. A seal is preferably provided on a leading or trailing surface or edge of the piston. In the case of a compressor a seal could be provided on a leading surface and in the case of an expander a seal could be provided on a trailing surface.
The rotor body is preferably rotatably supported by the stator rather than relying on co-operation between the pistons and the cylinder walls to relatively position the rotor body and stator.
It will be appreciated that this is distinct from a conventional reciprocating piston device in which the piston is maintained coaxial with the cylinder by suitable piston rings which give rise to relatively high friction forces.
The rotor ring is preferably rotatably supported by suitable bearing means carried by the stator.
Preferably the stator comprises at least one inlet port and at least one outlet port.
Preferably at least one of the ports is substantially adjacent to the shutter means.
Preferably the ratio of the angular velocity of the rotor to the angular velocity of the shutter disc is 1:1.
Multiple connected devices (whether in the form of compressors, expanders or other form) may be joined to one or more common intake outlet manifolds. This may be to so that a more continuous flow of gas is input or outputted (as the multiple devices may have different intake phases etc.). An example is a supercharger or compressor where two or more devices may be joined to a common output manifold to produce a nearly continuous output flow.
According to one aspect of the invention there is provided a rotary piston and cylinder assembly comprising two rotary piston and cylinder devices, and a transfer conduit, the transfer conduit fluidically connecting an outlet port of one device to an inlet port of the other device.
According to one aspect of the invention there is provided a rotary piston and cylinder assembly comprising two rotary piston and cylinder devices of the type set forth, a transfer conduit which connects an output port of one device to an input port of the other device, and the assembly further comprising heat transfer means for bringing exhaust fluid of the other device into thermal communication with fluid in the transfer conduit.
According to another aspect of the invention there is provided a rotary piston cylinder assembly comprising two rotary piston and cylinder devices of the type set forth, a transfer conduit which connects an output port of one device to an input port of the other device, and the assembly further comprising means for conveying exhaust fluid of the other device into the transfer conduit.
According to a further aspect of the invention there is provided a rotary piston and cylinder assembly comprising two rotary piston and cylinder devices of the type set forth and a transfer conduit that connects an output port of one device with an input port of the other device, wherein the transfer passage is provided with turbulence generating means which, in use, causes turbulent flow of fluid passing through the transfer passage.
According to another aspect of the invention there is provided a rotary piston and cylinder device comprising two rotary piston and cylinder devices of the type set forth and a transfer conduit which connects an output port of one device with an input port of the other device, the transfer conduit being provided with resonance control means which, in use, is operative to damp or amplify fluid pressure waves of fluid in the transfer conduit.
According to another aspect of the invention there is provided a rotary piston and cylinder device comprising two rotary piston and cylinder devices of the type set forth and a transfer conduit which connects an output part of one device with an input port of the other device, the transfer conduit being provided with compressed gas storage means, which in use, is operative to supply compressed gas into the transfer conduit.
According to a further aspect of the invention there is provided a rotary piston and cylinder device of the type set forth comprising an adjustable port arrangement, the adjustable port arrangement comprising a displaceable stator wall portion which is adapted to be movable relative to an aperture region provided in the stator which aperture region provides fluid communication between the cylinder space and a region external of the device, and the arrangement being such that the stator wall portion can be moved so as to alter the position and/or extent of the aperture relative to the annular cylinder space.
According to yet a further aspect of the invention there is provided a rotary piston and cylinder device of the type set forth in which the rotor is provided with an aperture region, and the stator is provided with an aperture region, at least one of the rotor and the stator being provided with a movable portion and when in communication, the aperture regions provide fluid communication between the annular cylinder space and a region external of the device, the arrangement of the device being such that, in use, the movable portion can be moved and so the angular extent of at least one of the aperture regions can be altered.
Another aspect of the invention relates to a rotary piston and cylinder assembly comprising two rotary piston and cylinder devices of the type set forth and a transfer conduit which connects an output port of one device with an input port of the other device, the transfer conduit being provided with acoustically absorbent means.
According to another aspect of the invention there is provided a rotary piston and cylinder device of the type set forth comprising an adjustable port arrangement, the adjustable port arrangement comprising a displaceable portion which is adapted to be moveable relative to an aperture region provided in the rotor, which aperture region provides fluid communication between the cylinder space and a region external of the cylinder space, and the arrangement being such that the displaceable portion can be moved so as to alter the position and/or extent of the aperture region relative to the cylinder space.
Yet a further aspect of the invention concerns an internal combustion engine comprising two piston and cylinder devices of the type set forth, a transfer conduit which connects an output port of one device to an input port of the other device and fuel injection means, the fuel injection means being arranged to issue fuel into the transfer conduit.